Compression unit for refrigerating systems



Sept. 1933. R. L. ALEXANDER ET AL 1,925,166

COMPRESSION UNIT FOR REFRIGERATING SYSTEMS Filed Aug. 21, 1930 ATTORNEYS Patented Sept. 5, 1933 UNITED STATES PATENT OFFICE COMPRESSION UNIT FOR REFRIGERATING SYSTEMS tion of Delaware Application August 21, 1930. Serial No. 476,736

1 Claim.

This invention relates to refrigeration systems and more particularly concerns an improved compression unit for use in refrigeration systems of the compression type.

Small electric refrigeration systems of the compression type are extensively used to cool household refrigerators, water coolers and the like. Compression refrigerating systems of this type include as essential elements thereof, a compressor for compressing the refrigerant employed and a motor or other suitable prime mover for driving the compressor. In domestic and other small installations, it is essential that the mechanism employed be very compact and it is further desirable that the system be capable of operating for extended periods without attention.

The present invention has for its object, the provision of an extremely compact and reliable compression unit for refrigerating systems of the compression type. In accordance with the invention, the unit is of the sealed type, that is, both the refrigerant compressor and the driving motor therefor are enclosed within a sealed compression casing, whereby leakage of refrigerant is prevented and the lubrication of the moving parts of the mechanism is simplified. More specifically, the invention relates to an improved unitary construction and assembly of the refrigerant compressor, the compressor driving motor and the compression casing enclosing these elements, which construction produces a simple, reliable, compact and comparatively inexpensive unit.

In general, the objects of our invention are carried out by employing a compressor having a vertical shaft and spaced end plates and by forming the lower end plate of this compressor integrally with the base plate of the compression casing which encloses the compressor and its driving motor. We prefer to mount the stator of the driving motor on the upped end plate of the compressor and to employ a common vertical motor and compressor shaft having a large hearing carried in the upper end plate of the compressor.

The invention will be best understood by reference to the accompanying drawing, in which a compression unit embodying the invention has been illustrated. In the drawing;

Figure 1 is a sectional elevation of a refrigeration unit embodying the invention; and

Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1 and viewedin the direction of the arrows.

Referring to the drawing, the disclosed embodiment of the invention comprises generally a compression casing C within which are enclosed a compressor P and a motor M. The compression casing C comprises a dome shaped shell 1 having a base plate 2 suitably sealed across the lower end thereof. The base plate 2 is preferably circular and is provided with a central raised portion 3 having a plane machined upper surface 4 thereon. The surface 4 forms the lower end plate of the compressor P. A journal opening 5 is formed in the upper surface 4 of the raised portion 3, and a bearing bushing 6 may be disposed in this opening if desired. The cylinder or wall member '7 of the compressor P is mounted on the surface 4 with its cylinder opening 8 concentrically disposed with respect to the journal opening 5, as shown in Fig. 2. An upper end plate 9 is mounted on the wall member '7, and the end plate 9 and wall member '1 are clamped together and to the surface 4 of the raised portion 3 on the base plate 2 by suitable means such as the machine screws 10. The upper end plate 9 is provided with an integral upwardly extending journal or bearing 11 provided with a bearing bushing 12, the journals 5 and llbeing in vertical axial alignment.

A vertical shaft 13 is carried in the bearings 5 and 11 and a circular eccentric 14 is formed integral with or suitably secured to this shaft between the upper end plate 9 and the surface 4. An annular piston 15 having an integral radially extending blade portion 16 is mounted within the cylinder opening 8 in the wall member 'I-and the eccentric 14 fits within and rotatably engages the circular central opening of the piston, as shown in Fig. 2. The radial blade portion 16 of the piston 15 extends within a recess 17 in the cylinder wall member '7 and is mounted for pivotal and reciprocating movement in this recess between a pair of substantially semi-circular blocks 18 which are carried in arcuate grooves in opposite sides of the recess 1'7, as shown. An intake port 19 for the compressor P extends through the raised portion 3 of the base plate 2 and communicates with the interior of the compressor cylinder opening 8 at a point adjacent one side of the piston blade 16 as shown in Fig. 2. The intake port 19 preferably communicates through a check valve 20 of suitable construction with a suction pipe 21 from the evaporator, not shown. The exhaust port 22 of the compressor P passes through the upper compressor end plate 9 and enters the cylinder opening 8 at a point adjacent to the opposite side of the piston blade portion 16 from that on which the intake port 19-is located. The exhaust 22 opens into the interior of the compression casing C through a leaf type check valve 23.

When the shaft 13 rotates in the direction indicated by the arrow in Fig. 2, the annular piston 15 is carried by the eccentric 14 through an eccentric path within the cylinder opening 8, thus drawing in refrigerant gas through the intake port 19 compressing this gas and forcing it around the cylinder opening 8 and discharging the compressed gas through theexhaust port 22 and check valve 23 into the interior of the compression casing C.

The stator 25 of the motor M is preferablycarried on the upper ends of a support or flange 26 which is fixed to the upper end plate 9 of the compressor. The rotor 27 of the motor is fixed to the upper end of the shaft 13 by suitable means and rotates within the stator in the usual manner. I

An oil duct 28 is preferably provided between the journal opening 5 and the interior of the compression casing C. Additional oil ducts 29 and 30 are provided in the shaft 13 to serve oil to the shaft and eccentric bearing surfaces. The compression casing C is preferably filled with lubricating oil to a level above the outer end of the duct 28, and the pressure developed within the casing by the discharge of compressed refrigerant therein through the compressor P forces the oil through the ducts 28, 29 and 30 to all of the bearing surfaces of the mechanism.

The motor M and compressor P are tightly sealed within the compression casing C. As shown, a depression or groove 31 is formed in the inner surface of the casing shell 1 near its lower edge, and the outer edge of the base plate 2 is fitted snugly within this depression. The base plate 2 is locked within the groove 31 by means of a split ring 32 of heavy resilient wire which is expanded into a recess 33 near the lower edge of the shell 1 and just below the lower surface of the base plate 2. The joint between the base plate 2 and the shell 1 is preferably sealed by tinning, soldering or welding, as shown at 34. The particular casing sealing means disclosed is claimed in our copending application, Serial No. 431,524, filed February 26, 1930.

The conductors 38 for supplying current to the motor M preferably pass through sealed openings 39 in the base plate 2.

The shell 1 of the compression casing C is preferably provided with suitable heat radiating means such as the fins 35. The casing C may be supported in any suitable manner but is preferably mounted in spaced relation to a surface by means of legs 36 or other suitable means.

The compressed refrigerant gas from the com- 4 pression casing C passes out through the pipe 37 to a condenser of suitable form which has been diagrammatically shown at S. The condenser may be of any suitable known construction and may be disposed in any desired position relative to the compression casing. The compressed refrigerant is liquefied in the condenser and delivered to a suitable evaporator, not shown, wherein the liquid refrigerantgasifies to produce the desired heat absorbing effect. The gaseous refrigerant from the evaporator is drawn to the compressor through the suction pipe 21.

From the description given, it will be apparent that the compression unit of the invention presents numerous advantageous features. The use of the compression casing base plate as the lower end plate of the compressor provides a very simple, compact and inexpensive arrangement. This arrangement permits the rapid transfer of heat from the cylinder of the compressor through the base plate to the surrounding atmosphere. The mounting of the compressor driving motor directly above and upon the upper end plate of the compressor adds to the compactness and simplicity of the construction and permits the use of a single shaft with only two bearings for both the motor and the compressor.

Although the disclosed embodiment of our compression unit includes a compressor of the eccentric piston type, it should be understood that various other types of compressors may be employed within the scope of the invention. Thus, according to our invention, gear or vane type compressors may be used and the compression casing base plate may be employed as the lower end plates of these or other types of compres sors.

We claim:

A compression unit for a refrigerating machine comprising a closed container including a base plate constituting a pressure retaining wall of the container, a supporting plate mounted in the container above and in spaced relation to said base plate, a bearing in said supporting plate and a shaft in said bearing, a piston and a cylinder surrounding said shaft below said supporting plate and in engagement with the lower surface thereof and with the upper surface of the base plate, a motor rotor on said shaft above said supporting plate and a motor stator carried on said supporting plate and surrounding said rotor.

ROBERT L. ALEXANDER. JAMES R. McCALLUM. 

